Atlanta and its neighbors in the Southeast seem to have settled into a permanent state of drought, but New York has the opposite problem: every year, the levels in the harbor rise. The two phenomena are flip sides of the same coin -- the inexorable and accelerating process of climate change, which presents a difficult set of problems for architects and urbanists. More and more firms are exploring ways to adapt to its effects and plan for the future. Jeff Byles explores why, when it comes to sustainability, blue is the new green.

One tenth of an inch may just be a splash. But sea level in New York creeps that much higher every year, and worsening climate impacts could make that splash several feet deep by the end of this century, meaning a soggier future for nearly one million of the region’s residents who live within three feet of the spring high-water mark. Factor in worsening storm surges, and today’s 100-year flood zone may well become a 10-year flood zone—wreaking $350 billion in damage to New York City under the severe scenarios the state’s Emergency Management Office is now studying.

“If you look where major development projects are going in New York, many are located right in harm’s way,” said Klaus Jacob, the outspoken Columbia University expert on sea-level rise, pointing to condos sprouting in Williamsburg or Columbia’s Manhattanville campus, sited at a vulnerable low point near the Hudson River. “That campus will start to look like Venice in a hundred years,” he warned.

London has its Thames Barrier. Dutch cities are fortified for the 10,000-year storm. But New York? “Coastal cities around the world that intend to be around for the next hundred years have done incredible work,” said Michael Fishman, founder of the consulting practice Urban Answers. “In North America, we have very little to show.”

That is starting to change as architects, ecologists, and engineers grapple with a hybrid of structure and landscape that is well-suited to the world’s rusting wharves. Some call it aquatecture—a new, blue alternative that is catching up with the green building movement as the next wave of sustainable urban design. “It’s not a building, not a pier, not a boat,” said Fishman, who teaches a waterfront studio at Columbia University’s Graduate School of Architecture, Planning, and Preservation (GSAPP). “It’s part water, part wildlife. Major development around the world is going to embrace this adaptation of post-industrial megastructures.”

In our wet new world, the postapocalyptic attitude is this: Bring it on. “Existing waterfront wetlands are going to be swamped,” said structural engineer Guy Nordenson, who is studying the consequences of sea-level rise with a multidisciplinary team that won the American Institute of Architects’ 2007 Latrobe Prize. They’ve hatched a radical proposal to revamp Upper New York Bay with an archipelago of hundreds of islands that would temper the destructive energy of storm surges. The proposal, which won a $100,000 award and will be refined in the coming months, presents a larger vision of New York Harbor as a focal point for regional development, like St. Mark’s Basin in Venice—a watery Central Park for the coming century.

Designers in New York and beyond are taking small steps toward Nordenson’s grand aquapolitan vision. A pair of projects from Boston-based Stoss Landscape Urbanism shows how modest interventions in the marine edge can prove paradigm-shifting in their own right. The firm lets flood conditions have their way with a waterfront site at Erie Street Plaza, located in Milwaukee, Wisconsin, at the confluence of the Milwaukee River and Lake Michigan. In the midst of a rough-edged working waterfront, the park contends with lake levels that rise and fall by as much as 6 feet over roughly 20-year cycles. Stoss’ solution was to slice slots into an existing steel bulkhead, allowing high lake levels to inundate a new zone of native grasses and revive a marsh condition long obliterated by industry.

At Bass River Park in West Dennis, Massachusetts, Stoss’ carpet of hillocks (below) fuels the free play of complex ecologies. Rising lake levels nourish a new marsh (above) at Milwaukee’s Erie Street Plaza, by the Boston-based Stoss.COURTESY STOSS LANDSCAPE URBANISM

It also makes a larger public point. “We’re allowing people to engage with this momentary high point of the lake cycle, so that it becomes very much an actor in the experience of that open space,” said principal Chris Reed. A similar strategy informed Bass River Park in West Dennis, Massachusetts, a 2.5-acre parcel that rests on land that was once salt marsh. Stoss designed zones of red cedar, sand plain, wet meadow, and salt marsh, each of which vies for botanical dominance amid changing climate variables. “We’re building in resilience and flexibility from an ecological standpoint,” Reed said. “No matter how high or low the sea level is, there are places where these individual plant communities can thrive.”

Showcasing water’s presence in the urban landscape required a complex approach for Margie Ruddick of Wallace Roberts & Todd (WRT), who has helped lead the design for a one-acre park at Queens Plaza. Working with artist Michael Singer, designers created a permeable paving system that features runnels with weep holes to collect water from paths and open spaces. A rain garden at the base of the Queensboro Bridge captures bridge runoff during storms, directing it to lush plantings. Below grade, a lozenge-shaped subsurface wetland detains water once it has filtered through street-level plantings. But working with water requires updated design chops. WRT and collaborators Marpillero Pollak Architects, who won a 2008 AIA New York chapter design award for the project, note that architects need to embrace a more unruly aesthetic. “A couple of years ago this project would have looked incomprehensible to a lot of architects,” Ruddick said. “There’s a kind of terror of things that don’t look organized and orderly.”

If a Category 4 cyclone hits the East River, Brooklyn Bridge Park will be exhibit A of that messiness. But it should still be around. In Michael Van Valkenburgh Associates’ design for the new public space, the sharp-edged bulkhead is banished in favor of a more natural riparian edge among adaptively reused piers. Careful thought is being given to storm threats, said principal Matthew Urbanski. “We’ve gone to great pains to shape the land in such a way that the significant tree plantings are above the 100-year flood level, so we don’t get salt-water inundation,” he explained. Beyond a calm-water basin that shelters small islands of natural habitat, a stabilized riprap edge protects against wave energy. Upland hills are planted with meadow grasses and canopy trees, while farther inland, freshwater swales capture stormwater from adjacent asphalt before it reaches the river.

“There’s a general consensus that we have to start working within the natural systems and reinforcing them,” said David Hamilton, principal of Praxis3, which won a recent round of The History Channel’s City of the Future competition with a proposal to liberate Atlanta’s natural streams from 1,900 miles of buried pipes and catchments. Contending with severe drought in the Southeast, Hamilton’s Atlanta-based team, in collaboration with EDAW, BNIM Architects, and environmental engineering firm Metcalf & Eddy, proposed a series of “waterscapes” to restore the natural watershed and spawn piedmont forest instead of sprawl. Existing drainage systems would be converted into aquifers to store ever-scarcer precipitation. The team aims to develop the idea as a model for drought-prone cities, where bureaucrats are perking up their ears. “When you start running out of water, politicians start paying attention in a hurry,” Hamilton said.

Breaching New Orleans’ levees would blunt the harm from Mississippi River floods, as in this high-density housing concept from Praxis3.COURTESY PRAXIS3 AND KEAN ARCHITECTS

New Orleans officials might want to consult his firm’s entry for a post-Katrina design competition that rethinks that city’s levee system. Collaborating with architect Lee Kean, Praxis3 proposed breaching floodwalls to create softer berms that ease over a block-size parcel in the Bywater neighborhood. Elevated green space weaves this natural terrain back into the city; a reflecting pool and cistern collect water on site. “The Mississippi River could actually go through its flood stages without doing any damage,” Hamilton said.

If there’s a bright side to climate change, it may be the opportunity to drag bolder designs out of the closet. “Some of these visionary projects are really legacies of the 1960s and ‘70s,” said architect Lindy Roy, who is studying the impacts of climate change in Africa with her students at Columbia’s GSAPP this semester. “We need to look at things with that kind of breadth. Otherwise, we make the sexy forms, and then all of the environmental stuff gets handed over to sustainability experts and engineers.”

In ARO’s vision of Manhattan now and in 2106 (left and right), melting polar ice caps make for a much soggier city. COURTESY ARCHITECTURE RESEARCH OFFICE

In other words, thinking the unthinkable can be an adventure. “Our goal is to make people excited instead of terrified,” said Adam Yarinsky, principal at Architecture Research Office (ARO), who is working with Nordenson’s Latrobe Prize team. ARO’s provocative entry for New York’s City of the Future episode did just that, making a virtue out of Gotham’s waterlogged fate. Envisioning low-lying neighborhoods deep-sixed under some 36 inches of water due to melting polar ice caps, ARO designed an optimistic new city for the year 2106, built of thin, pier-like buildings rising above Manhattan’s flooded downtown streets. Kayakers paddled languidly among ruined storefronts, as verdant public promenades bridged the waters overhead.

Take that, Rotterdam. When the big one hits, we may not be high and dry. But at least we’ll be floating in style.